KR102223504B1 - Quantum dot-resin nanocomposite and method of preparing same - Google Patents

Abstract

It provides a quantum dot-resin nanocomposite, a method of manufacturing the nanocomposite, and a molded article including the nanocomposite, in which a curable resin and a plurality of quantum dots are present in the form of nanoparticles.

Description

Quantum dot-resin nanocomposite and its manufacturing method {QUANTUM DOT-RESIN NANOCOMPOSITE AND METHOD OF PREPARING SAME}

It relates to a nanocomposite of a quantum dot and a resin and a method of manufacturing the same.

Quantum Dot (QD) is a semiconductor nanocrystal particle having a size of about 10 nm or less, and when synthesized in a colloidal state, the size can be freely controlled and particles having a relatively uniform size distribution can be synthesized. In addition, when the size is reduced to 10 nm or less, the energy density increases due to the quantum confinement effect of increasing the band gap as the size decreases. Accordingly, it is possible to have a band gap corresponding to visible light, and in the case of a quantum dot having a direct band gap, there is an advantage of further improving luminous efficiency.

Light-emitting diodes (LEDs) are a typical application example that takes advantage of quantum dots that can freely adjust wavelengths in the visible light region and have excellent light stability.In addition to general lighting, they can be used in various ways such as backlight units of display devices. Industrial demand is great. Current LED devices use a mixture of inorganic semiconductor materials, which makes it difficult to make white LEDs, and implements white by coating a phosphor that can be down-converted on top of UV or blue LEDs. earth-doped oxide) is difficult to control the emission wavelength and has low color purity. Therefore, it is necessary to develop a QD that can replace this.

In one embodiment, it is intended to provide a quantum dot-resin nanocomposite having increased structural and thermal stability.

In another embodiment, to provide a method of manufacturing a quantum dot-resin nanocomposite.

In another embodiment, it is intended to provide a molded article having a reduced coefficient of thermal expansion (CTE) including a quantum dot-resin nanocomposite.

In one embodiment, a curable resin and a plurality of quantum dots are present in the form of nanoparticles, and a quantum dot-resin nanocomposite is provided.

The nanocomposite is a form in which one or more quantum dots are encapsulated in a nanoparticle-type curable resin, a plurality of quantum dots coat the surface of a nanoparticle-type curable resin, or a plurality of quantum dots on a nanoparticle-type curable resin This can have a uniformly distributed shape.

The particle diameter of the quantum dot-resin nanocomposite may range from about 20 nm to about 5 μm.

The curable resin may be a thermosetting resin or a photocurable resin.

The quantum dot may be a quantum dot surface-coated with an organic substance substituent.

The organic substituents coated on the quantum dot surface are RCOOH, RNH ₂ , R ₂ NH, R ₃ N, RSH, R ₃ PO, R ₃ P, ROH, RCOOR' (where R, R'are each independently C1-C24 It may be an alkyl group of, or a C5-C24 aryl group), or a combination thereof.

Specifically, the organic substance substituent coated on the surface of the quantum dot is methane thiol, ethane thiol, propane thiol, butane thiol, pentane thiol, hexane thiol, octane thiol, dodecane thiol, hexadecane thiol, octadecane thiol, benzyl thiol; Methane amine, ethane amine, propan amine, butan amine, pentane amine, hexane amine, octane amine, dodecyl amine, hexadecyl amine, octadecyl amine, dimethyl amine, diethyl amine, dipropyl amine; Methanic acid, ethanic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, benzoic acid; Phosphines such as methyl phosphine, ethyl phosphine, propyl phosphine, butyl phosphine, and pentyl phosphine; Phosphine compounds or oxide compounds thereof such as methyl phosphine oxide, ethyl phosphine oxide, propyl phosphine oxide, and butyl phosphine oxide; Diphenyl phosphine, triphenyl phosphine compound or oxide compound thereof; Alternatively, it may be a material derived from phosphonic acid.

In another embodiment of the present invention, compared to a molded article containing a resin in which the resin alone or the quantum dot is simply dispersed in the resin, the coefficient of thermal expansion (CTE) is reduced by 30% or more, providing a molded article containing a resin nanocomposite.

The molded article may be a film, a display substrate, or a light emitting device.

In another embodiment of the present invention, an organic material, a resin, and a solvent to be substituted on the surface of the quantum dot are selected so that the organic material, resin, and solvent substituted on the surface of the quantum dot have a difference in solubility parameter, and the selected organic material is used. It provides a method of manufacturing a quantum dot-resin nanocomposite comprising emulsifying by mixing a substituted quantum dot, a resin, and a solvent.

The difference in the solubility parameter is that the solubility parameter of the solvent is the largest, the solubility parameter of the organic material substituted on the surface of the quantum dot is the smallest, and the solubility parameter of the resin is the solubility parameter of the solvent and the organic material substituted on the surface of the quantum dot. It may have a value between the solubility parameters.

The difference in the solubility parameter is that the solubility parameter of the resin is the largest, the solubility parameter of the organic material substituted on the quantum dot surface and the solvent have similar values, but the solubility parameter of the organic material substituted on the quantum dot surface is the solubility of the solvent. It may be larger than the parameter.

The difference in the solubility parameter is that the solubility parameter of the solvent is the largest, the organic material substituted on the quantum dot surface and the solubility parameter of the resin have similar values, but the solubility parameter of the resin is the solubility of the organic material substituted on the quantum dot surface. It may be larger than the parameter.

The resin may be a thermosetting resin or an ultraviolet curable resin.

The organic material substituted on the surface of the quantum dot is RCOOH, RNH ₂ , R ₂ NH, R ₃ N, RSH, R ₃ PO, R ₃ P, ROH, RCOOR' (where R, R'are each independently C1-C24 It may be an alkyl group of, or a C5-C24 aryl group), or a combination thereof.

The organic material substituted for the solvent, a resin, and a quantum dot surface may be one having a solubility parameter value of between about 10 MPa ^1/2 to about 30 MPa ^1/2, respectively.

The quantum dot-resin nanocomposite according to the above embodiment provides a structurally stable form by having a specific size or more, and thus, the lifespan may be increased compared to the case where the quantum dot alone exists. In addition, compared to a molded article containing a resin alone or a resin in which the quantum dots are simply dispersed, the molded article including the quantum dot-resin nanocomposite exhibits a significantly lower CTE.

1A is a schematic diagram schematically showing the shape of a quantum dot-resin nanocomposite manufactured according to an embodiment.
1B is a schematic diagram schematically showing the shape of a quantum dot-resin nanocomposite manufactured according to another embodiment.
2 is a case where only a solvent and a resin having a difference in solubility parameter are included (a), and when the solvent and resin, and quantum dots are included together (b), respectively, in a state of first mixing (left), and after mechanically stirring the mixture This is a picture showing the state left unattended for a certain period of time (right).
3 is a table showing the solubility parameters of photocurable resins (TE, PDMS, and 311RM) and organic materials (chloroform, hexane, oleic acid, TOA) used to replace the surface of a solvent or quantum dot.
FIG. 4 is an optical microscope photograph of the surface of the quantum dot used in the Example by substituting a polymer nucrel and dispersing it in a TE photocurable resin by mechanical agitation according to a conventional method, forming a film, and taking the surface of the film.
5 is an atomic force microscope (AFM) photograph showing the surface of a film manufactured including the quantum dot-resin nanocomposite prepared according to Example 1, (a) is an image according to the surface height (height image) ), and (b) is a photograph of a phase image showing the existence of different phases.
6 is an atomic force microscope (AFM) photograph showing the surface of a film manufactured including a quantum dot-resin nanocomposite prepared according to Example 2, (a) is an image according to the surface height (height image) ), and (b) is a photograph of a phase image showing the existence of different phases.
7 is an atomic force microscope (AFM) photograph showing the surface of a film manufactured including the quantum dot-resin nanocomposite prepared according to Example 3, (a) is an image according to the surface height (height image) ), and (b) is a photograph of a phase image showing the existence of different phases.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

In one embodiment of the present invention, there is provided a quantum dot-resin nanocomposite in which a curable resin and a plurality of quantum dots are in the form of nanoparticles.

The nanocomposite is a form in which one or more quantum dots are encapsulated in a nanoparticle-type curable resin, a plurality of quantum dots coat the surface of a nanoparticle-type curable resin, or a plurality of quantum dots on a nanoparticle-type curable resin This can have a uniformly distributed shape.

The particle diameter of the quantum dot-resin nanocomposite may range from about 20 nm to about 5 μm.

By using quantum dots (hereinafter referred to as'QD') as a color down converting material for light emitting devices (LEDs), attempts have been made to obtain superior efficiency and color purity compared to conventional phosphors. Since the theoretical QD has a quantum efficiency of 100% and a half width of less than 40 nm and has high color purity, QD is expected to significantly improve color reproducibility when applied to light-emitting devices compared to conventional inorganic phosphors.

However, while conventional inorganic phosphors are particles having a micron size, QDs having nano-sized (about 6 to 8 nm) have a problem of low life, and when applied to light-emitting devices, they have a lifespan of about 30,000 hours or more. In that a device that can be applied in practice can be developed only by securing a number of problems to be solved in manufacturing a light emitting device using quantum dots.

As one method for solving the above problem, in the prior art, an epoxy and a silicone resin (polymer) and QD nanoparticles were arbitrarily mixed and applied to the fabrication of a composite film and an LED chip. However, when QD is applied to LEDs, it is important to preserve the passivation layer of the QD surface well in order to maintain the efficiency and color reproducibility of the LED by maintaining high efficiency and color purity of the solution state. Currently, when distributing a light-emitting material to an LED chip, a method of simply mixing a polymer as an encapsulation material and a light-emitting material in a powder form, or using a dispersant to improve dispersion characteristics is applied. However, in the case of colloidal QD, the silicon used as an encapsulant and the organic matter on the QD surface are not compatible with each other, resulting in QD aggregation, and in the process, the organic matter on the QD surface is also lost. A decrease in efficiency occurs. In addition, it is difficult to achieve reproducibility when forming a complex with a polymer due to differences in the amount of organic matter remaining depending on the synthesis conditions and the degree of purification of QD. In addition, when a lot of organic substances are removed, even the surfactant on the QD surface is removed, and there is a problem that the separation of the QD and the passivation layer proceeds rapidly when driving for a long time. In addition, when QD light-emitting materials are dispersed in polymers and light (thermal) curing resins and injected into glass capillary for film and LED products and cured, the large coefficient of thermal expansion (CTE) of polymers and resins is affected. This causes a crack in the glass capillary and a problem in device manufacturing.

To solve this problem, control the CTE value of the QD/resin structure through the selection of the optimum resin having a low CTE value when manufacturing the QD/resin composite, and optimize the compatibility (dispersion) between QD and the resin. It is necessary to control QD luminance by preventing QD aggregation.

According to the above-described embodiment, since the quantum dots and the resin have the form of composite nanoparticles, unlike quantum dots simply dispersed in a conventional polymer matrix, the quantum dots can be manufactured with a more stable size and structure by the resin, As a result, it is possible to achieve structural stabilization and life-improving effects of quantum dots. In addition, as will be described later, in the molded article including the quantum dot-resin nanocomposite, the coefficient of thermal expansion decreases by 30% or more compared to the case where only the resin is present alone, or the quantum dot is simply dispersed in the resin. It can be very advantageous for applications that require application in.

The quantum dot-resin nanocomposite according to the above embodiment may be prepared by an emulsification method using a difference in solubility parameters between the quantum dot, the resin, and the solvent.

For example, by selecting a resin having the largest solubility parameter of the solvent, the smallest solubility parameter of the quantum dot, and having a solubility parameter value between the solubility parameter of the solvent and the solubility parameter of the quantum dots, and mixing them together to emulsify. Quantum dot-resin nanocomposite can be prepared.

Or, for example, the solubility parameter of the resin is the largest, the solubility parameter of the quantum dot and the solvent have similar values, but the solubility parameter of the quantum dot has a larger value than the solubility parameter of the solvent, a quantum dot, a solvent, and a resin are selected. , By mixing and emulsifying, it is possible to prepare a quantum dot-resin nanocomposite.

Or, for example, the solubility parameter of the solvent is the largest, the solubility parameter of the quantum dot and the resin have similar values, but the solubility parameter of the resin has a larger value than the solubility parameter of the quantum dot, quantum dots, solvent, and resin By selecting, mixing and emulsifying a quantum dot-resin nanocomposite can be prepared.

Here, the term'quantum dot solubility parameter' should be understood to mean a solubility parameter of an organic substance substituted with a quantum dot.

Therefore, in the manufacturing method, the organic material, resin, and solvent to be substituted on the surface of the quantum dot are selected so that the organic material, resin, and solvent substituted on the surface of the quantum dot have a difference in solubility parameter, and substituted with the selected organic material. It relates to a method for producing a quantum dot-resin nanocomposite comprising emulsifying a quantum dot, a resin, and a solvent by mixing.

An organic material substituted for a quantum dot is a material derived from a capping agent such as an organic surfactant or an amphiphilic polymer included in the manufacture of the quantum dot to protect the surface of the quantum dot. It is well known to those who possess it.

For example, the organic material is RCOOH, RNH ₂ , R ₂ NH, R ₃ N, RSH, R ₃ PO, R ₃ P, ROH, RCOOR' (where R, R'are each independently C1-C24 It may be an alkyl group, or a C5-C24 aryl group), or a material derived from a combination thereof. Specifically, the organic material is methane thiol, ethane thiol, propane thiol, butane thiol, pentane thiol, hexane thiol, octane thiol, dodecane thiol, hexadecane thiol, octadecane thiol, benzyl thiol; Methane amine, ethane amine, propan amine, butan amine, pentane amine, hexane amine, octane amine, dodecyl amine, hexadecyl amine, octadecyl amine, dimethyl amine, diethyl amine, dipropyl amine; Methanic acid, ethanic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, benzoic acid; Phosphines such as methyl phosphine, ethyl phosphine, propyl phosphine, butyl phosphine, and pentyl phosphine; Phosphine compounds or oxide compounds thereof such as methyl phosphine oxide, ethyl phosphine oxide, propyl phosphine oxide, and butyl phosphine oxide; Diphenyl phosphine, triphenyl phosphine compound or oxide compound thereof; It may be a material derived from phosphonic acid or the like, but is not limited thereto.

The resin may be a thermosetting resin or an ultraviolet curable resin.

As the thermosetting resin, epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, silicone, polyurethane, allyl resin and thermosetting acrylic resin, phenol-melamine condensation polymerization resin, urea melamine condensation polymerization resin, etc. can be used. In addition, it is possible to select and use an appropriate one from among those falling within the range of the solubility parameters described above. Further, the thermosetting resin is not limited to the above resins.

As the ultraviolet curable resin, a radical-polymerizable unsaturated group, such as a (meth)acryloyloxy group, a vinyloxy group, a styryl group, a vinyl group, and/or a cation-polymerizable group, such as an epoxy group, a thio It includes a resin containing a functional group such as an epoxy group, a vinyloxy group, and an oxetanyl group. Examples of these resins include polyester resins, polyether resins, (meth)acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiolpolyene resins. Can, and is not limited to these.

The semiconductor nanocrystal may include a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV compound, or a combination thereof.

The II-VI group compound is a binary compound selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, MgZnTe, HgZnS, MgZnTe Bovine compounds; And HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and GaN group III-V compounds selected from the group consisting of mixtures thereof , GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and a binary compound selected from the group consisting of a mixture thereof; A ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, and mixtures thereof; And GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and may be selected from the group consisting of a quaternary compound selected from the group consisting of a mixture thereof, The IV-VI compound is a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; A three-element compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; And SnPbSSe, SnPbSeTe, SnPbSTe, and may be selected from the group consisting of a quaternary compound selected from the group consisting of a mixture thereof, wherein the group IV compound is a single-element compound selected from the group consisting of Si, Ge, and mixtures thereof; And it may be selected from the group consisting of a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

The semiconductor nanocrystal may have a core-shell structure.

The semiconductor nanocrystals may absorb light having a wavelength of 300 nm to 500 nm and emit a wavelength of 500 nm to 600 nm, 600 nm to 700 nm, or 550 nm to 650 nm.

Depending on the difference in the solubility parameter, the shape of the produced quantum dot-resin nanocomposite may be different, respectively.

Here, "Solubility Parameter" means "Hilderbrand solubility parameter (δ)", and is a criterion for numerically evaluating the degree of interaction between substances. The solubility parameter is particularly well indicative of the solubility of non-polar materials, such as many polymeric materials. Substances with similar solubility parameter (δ) values can be mixed with each other. The solubility parameter may be expressed as the square root of cohesive energy density, as expressed by Equation 1 below:

(Equation 1)

In Equation 1, Vm is a molar volume, ΔHv is a difference in heat of vaporization, R is an ideal gas constant, and T is an absolute temperature.

"Agglomeration energy density" refers to the amount of energy required to completely separate one molecule from other molecules around it, which is equal to the heat of vaporization divided by the molar volume. In order for a substance to dissolve, it must be separated from the same molecules and completely surrounded by the solvent, so the same interactions must be overcome, and thus Dr. Joel Henry Hilderbrand proposed the square root of the cohesive energy density as a measure of solubility. Substances with similar solubility parameters can interact with each other and thus exhibit solvation, miscibility, or swelling.

Accordingly, for example, the solubility parameter of the solvent is the largest, the solubility parameter of the organic material substituted on the surface of the quantum dot is the smallest, and the solubility parameter of the resin is the solubility parameter of the solvent and the organic material substituted on the surface of the quantum dot. In the case of having a value between the solubility parameters of the material, the quantum dot-resin nanocomposite prepared therefrom may have a form in which one or more quantum dots are impregnated in the center of the resin in the form of nanoparticles.

On the other hand, when the solubility parameter of the resin is the largest, the solubility parameter of the organic material substituted on the surface of the quantum dot and the solvent have similar values, but the solubility parameter of the organic material substituted on the surface of the quantum dot is greater than the solubility parameter of the solvent , The quantum dot-resin nanocomposite prepared therefrom may be prepared in a form in which a plurality of quantum dots are coated on the resin surface in the form of nanoparticles.

In addition, the solubility parameter of the solvent is the largest, and the solubility parameter of the organic material and the resin substituted on the surface of the quantum dot have similar values, but the solubility parameter of the resin is larger than the solubility parameter of the organic material substituted on the surface of the quantum dot. In the case of having, the quantum dot-resin nanocomposite prepared therefrom may be prepared in a form in which a plurality of quantum dots are uniformly dispersed in a resin in the form of nanoparticles.

As described above, in the manufacturing method according to the embodiment of the present invention, the position of the quantum dot in the resin and the size of the quantum dot-resin nanocomposite are determined by adjusting and selecting the solubility parameter of the organic material, solvent, and resin substituted on the surface of the quantum dot. Can be controlled.

The organic material substituted for the solvent, a resin, and the quantum dot surface, solubility parameter, respectively, may have a value between about 10 MPa ^1/2 to about 30 MPa ^1/2, a solvent having a solubility parameter of this range, the resin From, and quantum dots, in consideration of the desired particle size and the position or distribution of the quantum dots in the particles, it may be used by selecting an appropriate quantum dot, a resin, and a solvent.

1 is a schematic diagram showing the shape of a quantum dot-resin nanocomposite according to an embodiment.

Referring to FIG. 1(a), a resin (2) is formed in the form of nanoparticles in a solvent (1), and a plurality of quantum dots (QD) (3) particles are encapsulated into the resin in the form of nanoparticles. You can see the structure. In this structure, the solvent having the largest solubility parameter and the QD having the smallest solubility parameter exist as far apart as possible because they are not friendly to each other, and for this purpose, a resin having a solubility parameter between the solvent and the QD is It acts like a surfactant between QDs and exists in the form of encapsulating quantum dots inside them.

1(b), resin (2) particles in the form of nanoparticles are formed in a solvent (1), and a plurality of smaller QD (3) particles coat the resin particles on the surfaces of the resin particles. It exists in the same form as one. This is a form in which the QD and the resin have similar solubility parameters and exist close to each other, but the QD has a smaller solubility parameter than the resin and has a larger solubility parameter than the solvent, so that the resin is in contact with the solvent in the form of coating nanoparticles.

The quantum dot-resin nanocomposites prepared in FIG. 1 exist in an emulsion state in a solvent, and when only the solvent is removed therefrom, as shown at the bottom of FIGS. 1(a) and 1(b), in the form of nanoparticles. The made-up quantum dot-resin nanocomposites can be obtained.

2 shows that the nanocomposite exists in an emulsion state in a solvent. In the case of (a) of FIG. 2, a state in which only a solvent and a resin are mixed before mixing the quantum dots (left), and a state after a certain time has elapsed after mixing by stirring the quantum dots (right). In other words, it shows that the solvent and the resin having a difference in solubility parameters do not exist in an emulsion state even if they are mixed, and phase separation between the solvent and the resin occurs again in the same form as the first time passes. However, in the case of mixing quantum dots substituted with organic materials here, as shown on the left side of FIG. 2(b), the quantum dots appear to exist only in the solvent at first, but when mixed by stirring, even if left to stand for a certain period of time , As shown on the right, it can be seen that the phase separation as in the first does not occur and exists in an emulsion state. That is, it can be seen that the quantum dot-resin nanocomposite as shown in the figure (a) or (b) of FIG. 1 is formed and exists in an emulsion state.

3 is a table showing the solubility parameters of resins, solvents, and quantum dot surface substituents used in Examples to be described later.

From the above table, it can be seen that the solubility parameter of the resin TE is the largest, and the solubility parameter of the PDMS or 311RM resin is lower.

In addition, chloroform, the solvent shown in the table above, has a higher solubility parameter than the hexane solvent, and the solubility parameters of oleic acid and TOA (trioctylamine), which are quantum dot surface substitution materials, are around 15, respectively, slightly higher than the hexane solvent, but similar solubility parameters. And, it can be seen that it has a lower solubility parameter than the chloroform solvent.

As can be seen from the examples described below, four kinds of quantum dot-resin nanocomposites were prepared by combining the resin, solvent, and substituents on the surface of the quantum dot shown in FIG. 3 as described in Table 1 according to the solubility parameter. The particle size and shape of the nanocomposite are listed in Table 2.

From Table 2, as a result of preparing a nanocomposite by combining a chloroform solvent having the largest solubility parameter, a TE resin having a lower solubility parameter, and a QD having the lowest solubility parameter, the particle size of the nanocomposite is about 40 nm, As expected, it can be seen that a quantum dot-resin nanocomposite in which QD is impregnated with resin TE is obtained. Fig. 5 shows an atomic force microscope (AFM) photograph of the film including the nanocomposite obtained therefrom. Figure 5 (a) shows the image (height image) according to the surface height of the nanocomposite film, (b) is a phase image photograph showing the existence of different phases on the surface. Bright dots are visible in the photo on the right side of FIG. 5, which are resin particles encapsulating quantum dots inside.

AFM photographs of the films produced including the nanocomposite prepared according to Example 2 and Example 3 are shown in Figs. 6 and 7, respectively, and in both Figs. 6 and 7, clearer nanocomposite particles can be seen. have.

On the other hand, from Table 2, the particle sizes of the nanocomposites according to Example 2 and Example 3 are about 50 nm and about 80 nm, respectively, and these have a slightly larger particle size than the nanocomposite of Example 1 in which QD is enclosed in a resin. You can see that you lost.

From FIGS. 5 to 7, the quantum dot-resin nanocomposite manufactured according to an embodiment of the present invention maintains the shape of the nanoparticles at the time of first manufacturing well even in the process of removing the solvent and forming a film after manufacturing, and the size is also It can be seen that it is less than 100 nm, and is well dispersed in the film in a small and uniform form.

On the other hand, FIG. 4 is an optical micrograph of a film formed into a film after replacing the surface of the quantum dot used in the Example with a Nucrel polymer, and then mechanically mixing and dispersing it in a TE photocurable resin according to a conventional method. to be. As can be seen from FIG. 4, in the case of simply dispersing quantum dots in a resin according to a conventional method, even if the surface of the quantum dots is replaced with a polymer, the substituted quantum dots are not well dispersed in the resin, and they aggregate to about 300 It can be seen that it exists in a large particle size up to µm.

On the other hand, as mentioned above, when the quantum dot-resin nanocomposite manufactured according to the above embodiment is manufactured as a molded article such as a film, surprisingly, about 30 compared to the case where the molded article is manufactured only with resin without including quantum dots. % Or more, such as at least about 35%, such as at least about 40%, such as at least about 45%, such as at least about 50%, it was found that the CTE value decreased.

In general, it is known that the coefficient of thermal expansion of organic materials such as resins is very large compared to inorganic materials, and this is considered to be an important drawback that limits the application of these organic materials to light-emitting devices that require high-temperature heat treatment. In order to solve this problem, a method of applying a mixture of an organic polymer and an inorganic material has been attempted, but a satisfactory level of CTE reduction effect was not obtained therefrom. However, according to the above embodiment, when the quantum dot-resin nanocomposite is formed, the CTE of the molded article including the same has a CTE reduction effect compared to a molded article prepared by simply dispersing the quantum dots in a polymer, or a molded article containing only a resin. It is remarkable.

Accordingly, in another embodiment of the present invention, as a molded article comprising the nanocomposite, a quantum dot-resin nanocomposite having a reduced coefficient of thermal expansion (CTE) of 30% or more compared to a molded article comprising only the curable resin constituting the nanocomposite. Provides included molded products.

As can be seen from the examples to be described later, the films prepared from resins containing nanocomposites prepared according to Examples 1 to 4, when each resin is included alone, or quantum dots are added to the resin according to a conventional method. Compared to the film prepared by simply dispersing, the coefficient of thermal expansion decreased by more than 30%. In particular, in the case of manufacturing a film by simply dispersing the quantum dots in a resin according to a conventional method, the CTE increases by about 30% or more compared to the case of manufacturing the film with the resin alone, whereas the nanocomposite form as in Examples 1 to 4 In the case of manufacturing a film by including it in a resin, the CTE is reduced by 30% or more compared to the case of forming the film with the resin alone, and this is about 50% when compared to the case of simply dispersing the conventional QD powder in the resin. It can be seen that CTE can be reduced to the above level.

Due to the reduced CTE, the molded article can be advantageously used in the manufacture of various molded articles that require heat treatment at high temperatures, and examples of such molded articles include films, display substrates, light emitting devices, and the like. Not limited.

Hereinafter, the implementation examples will be described through examples. However, these embodiments are only intended to specifically illustrate or describe the above embodiments, and thus the present invention is not limited thereto.

( Example )

Example 1 to 4: Quantum dots -Preparation of resin nanocomposite

As a quantum dot, a greenish QD based on InP-ZnS substituted with oleic acid (OA) on the surface is used, chloroform or hexane is used as a solvent, and 1,3,5-Triallyl-1,3,5-triazine is used as a resin. Thiolene consisting of a combination of -2,4,6(1 H ,3 H ,5 H )-trione (Aldrich-Sigma), Pentaerythritol tetrakis(3-mercaptopropionate) (Aldrich-Sigma), and Irgacure754 initiator (BASF) Using (TE) resin, or MINS-311RM (Minutatec, vinyl acrylate-based resin) resin, a quantum dot-resin nanocomposite was prepared using the set shown in Table 1 below.

Specifically, about 500 µl of a solvent containing quantum dots corresponding to about 1% by weight of the resin and 3 g of the resin were first mixed, sufficiently stirred for 30 minutes, and subjected to a solvent removal process in a vacuum atmosphere for 1 hour, each quantum dot- A resin nanocomposite was obtained.

The particle size of the obtained quantum dot-resin nanocomposite and the dispersibility of the resin and QD in the nanocomposite were measured using an atomic force microscope (AFM), and the results are shown in Table 2 below.

menstruum Quantum dots Suzy Example 1 chloroform InP-ZnS surface substituted with OA TE Example 2 Hexane InP-ZnS surface substituted with OA TE Example 3 chloroform InP-ZnS surface substituted with OA MINS-311RM Example 4 Hexane InP-ZnS surface substituted with OA MINS-311RM

Nanocomposite size shape Example 1 40 nm QD is encapsulated in resin Example 2 50 nm QD coated on the surface of resin particles Example 3 80 nm QD is uniformly dispersed in resin particles

Film manufacturing and evaluation

The quantum dot-resin nanocomposite prepared according to Examples 1 to 4 was mixed in the resin used in each production at a weight ratio of 20:80, and a nanocomposite-resin mixture was prepared between the upper and lower PET substrates with spacers. It is coated with a thickness of 100 μm, cured through a UV curing machine such as CL-1000 and Inocure-System, and the upper and lower PET substrates are removed to prepare a resin film containing nanocomposite.

The surface of the prepared film is photographed with an atomic force microscope (AFM), and is shown in FIGS. 5 to 7. 5 is a photograph of a film surface including a quantum dot-resin nanocomposite prepared according to Example 1, FIG. 6 is a photograph of a film surface including a quantum dot-resin nanocomposite prepared according to Example 2, and FIG. 7 is an implementation This is a photograph of a film surface including a quantum dot-resin nanocomposite prepared according to Example 3. From these surface photographs, it can be seen that the quantum dot-resin nanocomposite is uniformly dispersed in the prepared film.

Meanwhile, FIG. 4 is a comparative example of a film prepared by replacing the surface of the InP-ZnS quantum dot used in the above example with a polymer nucrel (manufactured by DuPont), and then mechanically dispersing it in a TE resin in an amount of 20% by weight. This is a picture of the AFM surface. In the case of FIG. 4, it can be seen that the quantum dots are not well dispersed and aggregated in the film, unlike the film photos of FIGS. 5 to 7 including the quantum dot-resin nanocomposite according to Examples 1 to 3. In this case, the size of the quantum dot aggregate is about 300 μm, which is so large that it cannot be compared with the dispersed size (100 nm or less) in the film of the quantum dot-resin nanocomposite according to the above embodiment.

In addition, the CTE of the prepared film was measured. At this time, for comparison, the CTE of the films prepared by dispersing the TE or 311RM resin alone or the QD used in the examples in the same amount in the resin in the same manner as in the conventional manner was also measured. The results are shown in Table 3 below.

film CTE ( ppmK ^-One ) TE sole film 160 QD dispersion TE film 200 Example 1 TE Film with Composite 125 Example 2 TE film with composite 148 311RM single film 136 QD dispersion 311RM film 181 Example 3 311RM Film with Composite 84 Example 4 311RM film containing composite 110

As can be seen from Table 3, when a film was prepared using the quantum dot-resin nanocomposite according to Examples 1 to 4, compared to the case where the resin alone or the QD powder was simply dispersed in the resin, the CTE was the resin alone. It can be seen that it decreased by more than 30% compared to the case of use. In particular, in the case of manufacturing a film by simply dispersing QD in a resin according to a conventional method, the CTE increased by about 30% or more compared to the case of manufacturing the film with the resin alone, whereas the same as in Examples 1 to 4 In the case of manufacturing a film by including it in a resin after manufacturing it in the form of a nanocomposite, CTE decreases by 30% or more compared to the case of forming a film with the resin alone, compared to the case of simply dispersing the existing QD powder in the resin. It can be seen that CTE can be reduced by about 50% or more.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also the right of the present invention. It belongs to the scope.

Claims (18)

Selecting an organic material, a curable resin, and a solvent to be substituted on the surface of the quantum dot so that the organic material, the curable resin, and the solvent substituted on the surface of the quantum dot have a difference in solubility parameter,
Treating the surface of the quantum dot with the selected organic material and replacing it,
As a method for producing a nanoparticle-shaped quantum dot-resin nanocomposite comprising emulsifying a quantum dot surface-substituted with the organic material by mixing the selected curable resin, and the solvent,
The solvent, the curable resin, and the organic material substituted on the surface of the quantum dot are selected so that the solubility parameter has a value between ^{10 MPa 1/2} to 30 MPa ^{1/2, respectively,}
The organic material substituted on the surface of the quantum dot is methanic acid, ethanic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, benzoic acid, or these Including a substance derived from an acid containing a combination of,
The resin includes a thiolene resin,
The difference in the solubility parameter is that the solubility parameter of the solvent is greater than the solubility parameter of the organic material substituted on the surface of the quantum dot and the solubility parameter of the resin, and the solubility parameter of the organic material substituted on the surface of the quantum dot is the smallest, and the solubility parameter of the resin is The method of manufacturing a quantum dot-resin nanocomposite having a value between the solubility parameter of the solvent and the solubility parameter of the organic material substituted on the surface of the quantum dot. delete delete delete The method of claim 1, wherein the organic material substituted on the surface of the quantum dot further comprises a material derived from thiol, amine, phosphine, or phosphoric acid. In clause 5,
The thiols include methane thiol, ethane thiol, propane thiol, butane thiol, pentane thiol, hexane thiol, octane thiol, dodecane thiol, hexadecane thiol, octadecane thiol, benzyl thiol, or combinations thereof;
The amine is methyl amine, ethyl amine, propyl amine, butyl amine, pentyl amine, hexyl amine, octyl amine, dodecyl amine, hexadecyl amine, octadecyl amine, dimethyl amine, diethyl amine, dipropyl amine, or their Includes a combination;
The phosphine is methyl phosphine, ethyl phosphine, propyl phosphine, butyl phosphine, pentyl phosphine, methyl phosphine oxide, ethyl phosphine oxide, propyl phosphine oxide, butyl phosphine oxide, diphenyl phosphine, tri A method for producing a quantum dot-resin nanocomposite comprising phenyl phosphine, diphenyl phosphine oxide, triphenyl phosphine oxide, phosphonic acid, or a combination thereof. delete A quantum dot-resin nanocomposite in which a curable resin and a plurality of quantum dots are formed according to the method of claim 1 in the form of nanoparticles. The quantum dot-resin nanocomposite of claim 8, wherein the quantum dot-resin nanocomposite is a form in which at least one quantum dot is encapsulated in a curable resin in the form of nanoparticles. delete delete The quantum dot-resin nanocomposite of claim 8, wherein the quantum dot-resin nanocomposite has a particle diameter of 20 nm to 5 µm. The quantum dot-resin nanocomposite of claim 8, wherein the curable resin is a thermosetting resin or a photocurable resin. delete Including the quantum dot-resin nanocomposite of claim 8, and a matrix resin,
A molded article having a reduced coefficient of thermal expansion (CTE) of 21.875% or more compared to a molded article composed of only curable resin constituting the nanocomposite. Including the quantum dot-resin nanocomposite of claim 8, and a matrix resin,
A molded article having a reduced coefficient of thermal expansion (CTE) of 30% or more compared to a molded article manufactured by dispersing the quantum dots in the matrix resin. The molded article of claim 15, wherein the molded article is a film, a display substrate, or a light emitting device. delete

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